The Supreme Court ruled today that California’s policy of temporarily segregating its incoming prisoners by race triggers “strict scrutiny,” reversing a Ninth Circuit court of appeals ruling that upheld the policy after subjecting it to a lesser level of scrutiny. It is, I suppose, good that the Court is reluctant to carve out exceptions to the general rule that any race-based classification is presumptively illegal; that, I am told, is why the Bush administration advocated the position the Court has taken. On the other hand, there is also a line of Supreme Court cases holding that prisoners’ constitutional rights generally get less protection than other citizens’, and dissenting Justice Thomas (joined by Scalia) is right that the Court does not persuasively explain why prisoners’ equal-protection rights ought to be given more protection than their free-speech rights.

The danger now is that courts will be tempted to water down the strict-scrutiny standard in order to uphold prison officials’ understandable desire to keep members of the Aryan Brotherhood from murdering members of the Black Guerrilla Family, to name just two prison gangs. And that dilution will then lead other courts to uphold racial classifications with more dubious and politically correct rationales, like the celebration of “diversity.”

Postscript: Justice Ginsburg, joined by Souter and Breyer, filed a concurring opinion, saying that she doesn’t think ALL racial classifications should be subjected to strict-scrutiny—that there should one (lenient) equal-protection standard for laws that are designed to help historically-discriminated against racial minorities, and another (strict) equal-protection standard for everything else. Unequal equal protection, in other words.